1. Field of the Invention
The present invention relates to a shutdown controlling method for a power system, especially to a shutdown controlling method that ensures electric apparatuses connected to the PDU having enough time to complete a shutdown process.
2. Description of Related Art
To easily shut down and power on multiple computers or servers at the same time, a power strip is proposed. The power strip has an AC power input, multiple AC power outlets and a power breaker. The power breaker is connected between the AC power input and the multiple AC power outlets in series. When the power breaker is turned on, an AC power input to the AC power input is transmitted to each of the AC power outlets. On the contrary, all AC power outlets do not output the AC power when the power breaker is turned off. Therefore, electronic apparatuses respectively connected to the AC power outlets can be shut down or powered on at the same time by turning off or on the power breaker of the power strip. However, parts of the electric apparatuses connected to the power strip have to be shut down or power on respectively. Therefore, an improved power strip with multiple power breakers is developed. The power breakers are connected to the corresponding AC power outlets to independently power on or off the corresponding AC power outlets. A manager manually controls the power breakers to determine a shutdown sequence and a power-on sequence for the electric apparatuses.
However, the manager has to remember the shutdown sequence and the power-on sequence for the electric apparatuses. When the power strip connects to a lot of the electric apparatuses, using the power strips is still not convenient.
Recently, a power distribution unit (PDU) is proposed. With reference to FIG. 7, the PDU 50 has an AC power input, multiple AC power outlets 51 and a controlling unit 52. When the AC power input is connected to an AC power source, each of the AC power outlets 51 can output an AC power. The controlling unit 52 stores parameters including a shutdown time and a power-on time for each AC power outlet 51. The manager presets the shutdown times and the power-on times of all the AC power outlets 51. At the shutdown time, the controlling unit 52 sequentially stops outputting the AC power of the AC power outlets 51 to shut down the electric apparatuses 30. Therefore, the PDU 50 can automatically turn off the electric apparatuses 30 in sequence and ensure that each electric apparatus 30 has enough time to completely shut down.
Based on the foregoing description, the manager conveniently shuts down the electric apparatuses by using the PDU. However, shutdown the electric apparatus may require different time to safely shut down, i.e. having different shutdown periods, so the manager has to change the parameters stored in the PDU. Therefore, the PDU has to require a convenient controlling system to preset parameters.
US Patent Application Pub. No. 20120119577—hereinafter “US20120119577” entitled “Smart Power Sockets, Boards, and Plugs” disclosed an approach is provided where a smart socket receives a request over a power line and generates a second request based on the received request. The second request is transmitted over a power cord connecting the smart power socket to a device. The device determines whether power is still needed at the device in order to perform one or more device operations. Thus, US20120119577 is only used for a device having the above determining function.
A non-patent document entitled “Power Panel® Business Edition User's Manual, Aug. 20, 2010” issued by CyberPower Inc. introduces a management software applied to UPS systems. As disclosed on page 40 of the user's manual, a function “Prevent Early Off” of the management software installed in a client computer avoids an unsafely shutdown by sending a signal to a PDU. However, the protection function is only provided to the client computer with the management software installed therein. For other client computers without the management software installed therein, these client computers do not possess the “Prevent Early Off” function even though they are connected to the same PDU. Therefore, these client computers may still encounter the problem of unsafely shutdown. Thus, the above client computer is similar to the device of US20120119577, each of the above client computers needs to install a “Prevent Early Off” software.